In general, it is difficult to achieve, in a pneumatic tire, both of the running performance on snow and the running performance on dry road surfaces. For example, a pneumatic tire for use on icy and snowy roads has a tread portion in which multiple main grooves each extending in the tire circumferential direction and multiple lug grooves each extending in the tire width direction are provided, so that a large number of blocks are defined by these main grooves and lug grooves (see, for example, Patent Document 1). Such a pneumatic tire for use on icy and snowy roads is capable of exerting, with an increased groove area, an excellent running performance on snow. However, such pneumatic tire for use on icy and snowy roads is insufficient in block rigidity because a soft tread rubber is employed in general. For this reason, currently-available pneumatic tires for use on icy and snowy roads are not satisfactory in the driving stability and wear resistance on dry road surfaces.
Patent Document 1: Japanese patent application Kokai publication No. 2004-34903